1. Field of the Invention
The invention relates to an outside structure conformal antenna and in particular, to a flat broadband antenna in a supporting structure of a vehicle and more specifically an aircraft, whereby the supporting structure is in particular a supporting system primary structure.
2. Discussion of Background Information
The term “aircraft” relates to all conceivable devices that can be propelled through the air by any drives, devices such as airplanes, helicopters, airships, drones, rockets, and the like. The example of rockets shows that the invention can also relate to aircraft or missiles that are suitable to fly both in the air and in space.
The increasing number of avionic functions in aircraft, in particular in airplanes, also causes the required number of antennae to rise correspondingly. Today, up to 60-antennae systems and more are no longer a rarity. This problem requires new ways of mounting or housing antennae, e g., in airplanes. A potential solution of this problem is the integration of the antennae into the supporting structures of vehicles and/or aircraft.
For the solution of the stated problem it must also be taken into account that the use of future airborne data transmission systems requires a large high frequency (HF) bandwidth because of immense amounts of data. For this reason, increasingly higher frequencies are used. At present, the market largely offers systems in the X or Ku band.
In addition to the demand for a large bandwidth, naturally a long data transmission range is demanded. This can only be achieved by antennae with a correspondingly big aperture or with arrays that are composed of several individual radiators. Airborne pivoting reflector antennae are now available as commercial products. Their housing, however, is usually a problem. Therefore, consideration has also already been given to using parts of, e.g., the airplane surface as a radiating aperture instead of using a relatively big reflector antenna.
Up to now, e.g., an airplane structure has had the exclusive function of fulfilling load-carrying and aerodynamic tasks. The structural surface correspondingly has had to withstand various mechanical loads.
With the expansion of the function of the structural surface of aircraft to act also as an antenna, additional problems arise in terms of the stability of the structures. For electronic reasons, suitable materials must be used for the antennae; thereby, however, the load-carrying function of the structure must not be affected adversely.
For the aforementioned reasons, the experts are increasingly refraining from building or using antennae that stand out from the structure or the outer shell of vehicles and/or aircraft in the form of rods, spirals, horn parts or other shapes. Thus, flow resistances can be diminished, and the danger of purely mechanical damage to the antennae can at least be reduced somewhat.
The mentioned problem led to the development of outside structure conformal antennae and to their alignment with the predetermined form of structures in vehicles and/or aircraft as far as possible or in an optimal, i.e., identical manner.
For the known prior art in this matter, reference is made to a publication by Dipl.-Ing. Robert Sekora et al. with the title “Conformal Airborne Array Antenna for Broad Band Data Link Applications in the X-Band.” This treatise essentially shows the differences between conventional and more up-to-date outside structure conformal antenna systems that are closely aligned with the structure—in this case that of airplanes.
Another pertinent prepublication, also by Dipl.-Ing. Robert Sekora, entitled “Strukturintegrierte Flugzeugantenne für Breitbandanwendungen im X-Band.” In this publication, the author explains the structural integrability of an array antenna. Furthermore, the structural setup in terms of its electromagnetic function is confirmed.